Aims: To compare the effects of 2 and 5 min of passive static stretching (SS) on stiffness and blood flow in the rectus femoris in adolescent athletes using shear wave elastography (SWE) and superb microvascular imaging (SMI).Material and methods: This prospective study included 20 male athletes with median age of 14.5 (12.5–16.5) years. The subjects were divided into two groups based on the SS duration as follows: 2 min (n=10) and 5 min (n=10). At rest and after 2 and 5 min of SS, stiffness and blood flow values were compared in the rectus femoris for each group. Inter-operator reliability was also analysed.Results: There was no significant difference between resting and 2 min of SS in terms of stiffness. The stiffness values decreased significantly from resting to 5 min of SS. The blood flow increased significantly from resting to 2 and 5 min of SS. Inter-operator reliability was moderate to perfect for SWE and SMI measurements (ICC: 0.52–0.83).Conclusions: SWE and SMI can be used to acquire reliable quantitative data about muscle stiffness and blood flow in adolescents. While stiffness parameters significantly decreased from resting after only 5 min, blood flow significantly increased both after 2 and 5 min. For physical rehabilitation protocols, 5 min of SS may be chosen to reduce stiffness. For competitions, 2 min of SS may be sufficient for warm-up exercise because it increases the blood flow optimally. Five min of SS may be preferred for the cool-down exercise to enhance recovery.

İzokinetik testler, sporcuların atletik performansını mekanik yönleriyle ortaya koyar. Ancak mekanik terimlerin anlamı spor bilimciler tarafından net bir şekilde bilinmemektedir. Bu sebeple testten elde edilen mekanik çıktıların atletik performanstaki karşılığı da anlaşılamamaktadır. Kuvvet, tork, yapılan iş ya da üretilen güç gibi terimler birbiriyle bağlantılıdır; fakat birbirinden farklı atletik performans özelliklerini ifade eder. Bu terimlerin anlamı ve performanstaki yansımalarının bilinmemesi sporcuların performansının yanlış değerlendirilmesine sebep olmaktadır. Ayrıca terimlerin yanlış kullanılması biyomekanik ve spor bilimleri camiası arasında bir iletişim engeli oluşturmaktadır. Bu sebeple bu çalışmada izokinetik testlerde kullanılan temel mekanik parametrelerin hem ölçüm hem de matematiksel hesaplama yöntemleri ile elde edilmeleri amaçlanmıştır. Ayrıca bu parametrelerin atletik performans açısından kullanımları değerlendirilmiştir. Bu çalışmada bir sprinterden pilot ölçüm alınmıştır. İzokinetik test baskın bacakta ve oturur pozisyonda diz ekleminde 60-120-240 der/s hızlarda uygulanmıştır. İzokinetik test ile eklem torkunun zamana, açıya ve hıza bağlı değişim grafikleri elde edilmiş ve bu veriler kullanılarak eklemin hareket boyunca yaptığı iş, ürettiği güç ve tepe torka ulaştığı açı değerleri hesaplanmıştır. Ayrıca birbirinden farklı birçok izokinetik test çıktısının beraber yorumlanarak performansın nasıl değerlendirileceği vurgulanmıştır. Patlayıcı kuvvet, çabukluk ve çabuk kuvvette devamlılık gibi atletik performans ölçümleri ile izokinetik test sonuçları arasındaki korelasyon ve anlamlı ilişkiler farklı spor disiplinleri içerisinde örneklendirilmiştir.

This study examined exploratory associations between isokinetic knee and hip variables and video-derived contact time across sprint acceleration. Nineteen male sprinters completed 60 m sprints; photocell timing gates recorded sprint times, and eight high-speed cameras operating at 240 frames/s provided contact and flight times. Bilateral concentric knee and hip flexion–extension were assessed at 60°/s and 240°/s for peak torque, relative peak torque, peak power, relative peak power, time to peak torque, and joint angle at peak torque. No statistically significant inter-limb differences were detected in the four torque/power outcomes or mean contact time. Two exploratory knee-extension comparisons at 240°/s yielded nominal raw p values below 0.05 for joint angle and time to peak torque, but neither remained statistically significant after Benjamini–Hochberg correction across 16 temporal/angular comparisons. After correction within four complete correlation families, 4 of 26 sprint-time–contact-time correlations remained statistically significant, all involving non-dominant-limb contact time. None of the 832 torque–contact-time, 832 power–contact-time, or 832 time-to-peak-torque/joint-angle-at-peak-torque–contact-time correlations remained significant. The isokinetic correlation patterns are therefore exploratory and require confirmation in larger samples using contact-time methods with established reliability and adequate temporal precision.

Aim: The aim of this study was to determine normative data for fat mass (FM), muscle mass (MM), and fat-free mass (FFM) in elite female volleyball players and to examine interlimb differences in body composition. Method: A total of 34 elite volleyball players participated in the study. Body composition was assessed using the bioelectrical impedance analysis (BIA) method. All measurements were performed in the morning, between 08:00 and 10:00 a.m., under controlled laboratory conditions (22–24 °C). Athletes were instructed to avoid food intake for at least 12 hours, and to refrain from caffeine, alcohol, and strenuous exercise 24 hours prior to testing. Results: The mean values for fat mass, lean body mass, and total body water were 13.26 ± 4.62 kg, 53.81 ± 7.95 kg, and 30.80 ± 12.09 L, respectively. Comparisons of FM, FFM, and MM between limbs revealed no statistically significant differences (p > 0.05). In the comparison between dominant and non-dominant legs, the p-values for fat mass, FFM, and MM were 0.058, 0.066, and 0.071, respectively, whereas the corresponding values for the arms were 0.070, 0.384, and 0.281. Conclusion: Although no significant morphological differences were detected between limbs, minor asymmetries may exist at the functional level. These findings indicate that elite female volleyball players exhibit a well-balanced body composition profile. Future research is recommended to integrate muscle tone and stiffness measurements to better understand the relationship between morphological and functional asymmetries.